Re: [PATCH] ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()

[Andrew Morton]

On Tue, 21 Jul 2026 19:49:16 +0800 Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx> wrote:

> o2hb_region_pin() is always called with the o2hb_live_lock spinlock held
> (from o2hb_region_inc_user() and o2hb_heartbeat_group_drop_item()), but it
> calls o2nm_depend_item() -> configfs_depend_item(), which sleeps: it pins
> the configfs filesystem and takes the configfs root inode rwsem. Under
> CONFIG_DEBUG_ATOMIC_SLEEP this triggers:
> 
>   BUG: sleeping function called from invalid context at kernel/locking/rwsem.c
>   in_atomic(): 1, ... name: mount.ocfs2
>     down_write
>     configfs_depend_item
>     o2hb_region_pin
>     o2hb_region_inc_user
>     o2hb_register_callback
>     dlm_register_domain_handlers
>     ...
>     ocfs2_dlm_init
>     ocfs2_mount_volume
>     ocfs2_fill_super
> 
> Rework o2hb_region_pin() to pin one region at a time with the lock
> dropped across the sleeping call: under o2hb_live_lock find the next
> eligible region and take a config_item reference to keep it alive, drop
> the lock, call o2nm_depend_item(), then retake the lock and record the
> pin. The config_item_put() is done with the lock released as well, since
> o2hb_region_release() also acquires o2hb_live_lock and can sleep. The
> region list may change while unlocked, so the scan restarts from the
> top after each pin. Local heartbeat still pins only the matching region;
> global heartbeat pins all eligible regions.

Thanks, I'll add cc:stable to this.

Sashiko might have a found a couple of pre-existing issues in there:

https://sashiko.dev/#/patchset/20260721114916.2098617-1-joseph.qi@xxxxxxxxxxxxxxxxx